筋材连接形式对有限空间加筋土挡墙抗震性能影响

    Effect of reinforcement connection form on seismic performance of reinforced soil retaining walls in limited space

    • 摘要: 为了解筋材连接形式对有限空间加筋土挡墙抗震性能的影响,开展筋材无连接、摩擦连接、机械连接振动台试验,探究3组试验加速度响应、面板位移、动力特性、筋材应变、潜在破裂面等变化规律。研究结果表明:3组试验加速度放大系数沿墙高呈非线性分布,并在挡墙顶部达到峰值。墙面永久位移峰值分别为0.138%H,0.034%H,0.015%H,机械连接较无连接减少89.13%,筋材反卷较无连接减少75.36%。试验结束后挡墙自振频率均有所下降,降幅分别为1.22%,0.81%,0.52%,结构内部虽有些许损伤但其仍具有良好的整体性。筋材拉力增量随输入加速度幅值增大而增大,并沿墙高呈非线性变化。实测潜在破裂面形式与现有规范破裂面形式有所差异,机械连接潜在破裂面为一条穿过墙趾并且沿后部稳定陡坡面的双折线。综合试验数据表明,筋材机械式连接较筋材反卷式在墙面永久位移、动力特性等方面表现出更为优越的抗震性能,但施工设计时应注意其墙后连接处的加固。

       

      Abstract: In order to understand the influence of the reinforcement connection form on the seismic performance of the SMSE wall, shaking table tests are carried out on three reinforcement connection types: non-connection, friction connection and mechanical connection. The evolution laws of acceleration response, panel displacement, dynamic characteristics, reinforcement strain, and potential fracture surface of the three groups of tests are explored. The results show that the acceleration amplification coefficient of the three groups of experiments is nonlinearly distributed along the wall height and reaches the peak value at the top of the retaining wall. The peak values of permanent displacement of the wall are 0.138%, 0.034% and 0.015% of the wall height, respectively, the mechanical connection is reduced by 89.13% compared with the non-connection, and the rewinding-type connection is reduced by 75.36% compared with the non-connection. After the test, the natural frequency of the retaining wall decreases, with a decrease of 1.22%, 0.81% and 0.52%, respectively. The tensile force increment of the reinforcement increases with the increase of input acceleration amplitude, and changes nonlinearly along the wall height. The measured potential fracture surface form is different from the existing standard fracture surface form, and the mechanical connection potential fracture surface is a double-folded line that passes through the wall toe and stabilizes the steep slope surface along the rear. The comprehensive test data show that the mechanical connection of the reinforcement shows etter seismic performance in terms of permanent displacement and dynamic characteristics of the wall than the rewinding type of reinforcement, but attention should be paid to the reinforcement of the connection behind the wall in the construction design.

       

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